Jason Mak, MD
NPI 1851450456 · Nephrology Physician · Fontana, CA
Enrolled with Medicare as Practitioner - Internal Medicine · source: CMS PECOS Public Provider Enrollment (2026.04.01)
Jason Mak, MD is a Nephrology Physician provider in Fontana, CA (NPI 1851450456).
Provider details
- NPI number
- 1851450456
- Entity type
- Individual
- Primary specialty
- Nephrology PhysicianAllopathic & Osteopathic Physicians
- Credential
- MD
- Sex
- Male
- Sole proprietor
- No
- License
- G50436 (CA)
Specialties & taxonomies
Allopathic & Osteopathic Physicians
Profile Score
A profile completeness & documented-activity index — NOT a quality, outcomes, or patient-satisfaction rating.
- Registry tenure38% of score
19 yrs in NPPES registry
- Profile completeness38% of score
100% of core fields populated
- Practice footprint23% of score
1 documented practice location
Signals a provider has no public data for (e.g. Medicare claims) are left out of the score entirely — never counted as zero — so providers without that data are not penalized. See the full formula and weights in our methodology.
Practice location
Mailing address
Registry dates
- Enumerated
- 2006-12-08
- Last updated
- 2021-12-01
Frequently asked questions
- What is Jason Mak's NPI number?
- Jason Mak's National Provider Identifier (NPI) is 1851450456, a unique 10-digit ID issued by CMS for use in standard healthcare transactions.
- What is Jason Mak's specialty?
- Jason Mak is listed in the NPPES registry with a primary specialty of Nephrology Physician (Allopathic & Osteopathic Physicians).
- Where is Jason Mak located?
- Jason Mak's practice location on file with NPPES is 9961 Sierra Ave, Fontana, CA 92335-6720.
- What is Jason Mak's phone number?
- The practice phone number listed in the NPPES registry for Jason Mak is (909) 427-3910.
- Does Jason Mak accept Medicare?
- Jason Mak is approved to bill Medicare according to CMS PECOS enrollment data (2026.04.01). Confirm current participation with the provider before scheduling.
- Is Jason Mak's NPI active?
- Yes — Jason Mak's NPI (1851450456) is active in the NPPES registry as of the last update on 2021-12-01.
Source: CMS NPPES Data Dissemination (June 2026). NPI Central is not affiliated with CMS. Data is provided as-is from the public registry.